Problem: A circle has a sector with area $\dfrac{96}{5}\pi$ and central angle $108^\circ$. What is the area of the circle? {64\pi} \color{#9D38BD}{108^\circ} {\dfrac{96}{5}\pi}
Explanation: The ratio between the sector's central angle $\theta$ and $360^\circ$ is equal to the ratio between the sector's area, $A_s$ , and the whole circle's area, $A_c$ $\dfrac{\theta}{360^\circ} = \dfrac{A_s}{A_c}$ $\dfrac{108^\circ}{360^\circ} = \dfrac{96}{5}\pi \div A_c$ $\dfrac{3}{10} = \dfrac{96}{5}\pi \div A_c$ $A_c \times \dfrac{3}{10} = \dfrac{96}{5}\pi$ $A_c = \dfrac{96}{5}\pi \times \dfrac{10}{3}$ $A_c = 64\pi$